You're a nice sibling!
If she's going to be a "serious" (no, there's no accepted definition of that) rider, then lights are nice. Everybody's got an opinion, but you won't go wrong with a Cygolite Dash 460 front lamp and Planet Bike Grateful Red rear.
If she's not a serious rider, then how about some Reelight CHPs? Always there if you need them; no batteries to go dead.
https://www.reelight.com/collections...s/products/cph
Or maybe I've completely misunderstood what you meant by 'pimp'. Monkeylectric:
https://youtu.be/OptX6mYjONY
I think you have the correct understanding.... sorta like "pimp my car"